The main concern would be that your kitten would get too stuffed up to smell, thus want, food. When baby animals don't eat or drink they get hypoglycemic (spelling?) and dehydrated so quickly and can die. We've seen a few babies at work so close to death or already gone because of that. Its so sad.

I don't say that to scare you, just to make sure you are watching that they are eating and drinking if you decide to wait the URI out.

I would shop around to at least get into a different vet that has lower costs. Some vets offer a second pet discount for exams if you needed to bring both little ones.

When we adopted Hermoine, she got a URI so bad that the tissue surrounding her windpipe was so swollen they were concerned she'd suffocate. Thankfully, the shots of cortosone worked. She wouldn't eat anything, because she couldn't smell anything either. She had to eat because the antibiotic made her tummy hurt otherwise. I was so worried, I tried everything, finally forcing tuna juice into her mouth. It was horrible. $350 later....